/*
 * Copyright 2002-2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.context.jdbc;

import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.style.ToStringCreator;
import org.springframework.jdbc.datasource.init.ScriptUtils;
import org.springframework.test.context.jdbc.SqlConfig.ErrorMode;
import org.springframework.test.context.jdbc.SqlConfig.TransactionMode;
import org.springframework.util.Assert;

/**
 * {@code MergedSqlConfig} encapsulates the <em>merged</em> {@link SqlConfig @SqlConfig}
 * attributes declared locally via {@link Sql#config} and globally as a class-level annotation.
 *
 * <p>Explicit local configuration attributes override global configuration attributes.
 *
 * @author Sam Brannen
 * @see SqlConfig
 * @since 4.1
 */
class MergedSqlConfig {

    private final String dataSource;

    private final String transactionManager;

    private final TransactionMode transactionMode;

    private final String encoding;

    private final String separator;

    private final String commentPrefix;

    private final String blockCommentStartDelimiter;

    private final String blockCommentEndDelimiter;

    private final ErrorMode errorMode;


    /**
     * Construct a {@code MergedSqlConfig} instance by merging the configuration
     * from the supplied local (potentially method-level) {@code @SqlConfig} annotation
     * with class-level configuration discovered on the supplied {@code testClass}.
     * <p>Local configuration overrides class-level configuration.
     * <p>If the test class is not annotated with {@code @SqlConfig}, no merging
     * takes place and the local configuration is used "as is".
     */
    MergedSqlConfig(SqlConfig localSqlConfig, Class<?> testClass) {
        Assert.notNull(localSqlConfig, "Local @SqlConfig must not be null");
        Assert.notNull(testClass, "testClass must not be null");

        // Get global attributes, if any.
        AnnotationAttributes attributes = AnnotatedElementUtils.findMergedAnnotationAttributes(
                testClass, SqlConfig.class.getName(), false, false);

        // Override global attributes with local attributes.
        if (attributes != null) {
            for (String key : attributes.keySet()) {
                Object value = AnnotationUtils.getValue(localSqlConfig, key);
                if (value != null) {
                    // Is the value explicit (i.e., not a 'default')?
                    if (!value.equals("") && value != TransactionMode.DEFAULT && value != ErrorMode.DEFAULT) {
                        attributes.put(key, value);
                    }
                }
            }
        }
        else {
            // Otherwise, use local attributes only.
            attributes = AnnotationUtils.getAnnotationAttributes(localSqlConfig, false, false);
        }

        this.dataSource = attributes.getString("dataSource");
        this.transactionManager = attributes.getString("transactionManager");
        this.transactionMode = getEnum(attributes, "transactionMode", TransactionMode.DEFAULT, TransactionMode.INFERRED);
        this.encoding = attributes.getString("encoding");
        this.separator = getString(attributes, "separator", ScriptUtils.DEFAULT_STATEMENT_SEPARATOR);
        this.commentPrefix = getString(attributes, "commentPrefix", ScriptUtils.DEFAULT_COMMENT_PREFIX);
        this.blockCommentStartDelimiter = getString(attributes, "blockCommentStartDelimiter",
                ScriptUtils.DEFAULT_BLOCK_COMMENT_START_DELIMITER);
        this.blockCommentEndDelimiter = getString(attributes, "blockCommentEndDelimiter",
                ScriptUtils.DEFAULT_BLOCK_COMMENT_END_DELIMITER);
        this.errorMode = getEnum(attributes, "errorMode", ErrorMode.DEFAULT, ErrorMode.FAIL_ON_ERROR);
    }

    private static <E extends Enum<?>> E getEnum(AnnotationAttributes attributes, String attributeName,
                                                 E inheritedOrDefaultValue, E defaultValue) {

        E value = attributes.getEnum(attributeName);
        if (value == inheritedOrDefaultValue) {
            value = defaultValue;
        }
        return value;
    }

    private static String getString(AnnotationAttributes attributes, String attributeName, String defaultValue) {
        String value = attributes.getString(attributeName);
        if ("".equals(value)) {
            value = defaultValue;
        }
        return value;
    }

    /**
     * @see SqlConfig#dataSource()
     */
    String getDataSource() {
        return this.dataSource;
    }

    /**
     * @see SqlConfig#transactionManager()
     */
    String getTransactionManager() {
        return this.transactionManager;
    }

    /**
     * @see SqlConfig#transactionMode()
     */
    TransactionMode getTransactionMode() {
        return this.transactionMode;
    }

    /**
     * @see SqlConfig#encoding()
     */
    String getEncoding() {
        return this.encoding;
    }

    /**
     * @see SqlConfig#separator()
     */
    String getSeparator() {
        return this.separator;
    }

    /**
     * @see SqlConfig#commentPrefix()
     */
    String getCommentPrefix() {
        return this.commentPrefix;
    }

    /**
     * @see SqlConfig#blockCommentStartDelimiter()
     */
    String getBlockCommentStartDelimiter() {
        return this.blockCommentStartDelimiter;
    }

    /**
     * @see SqlConfig#blockCommentEndDelimiter()
     */
    String getBlockCommentEndDelimiter() {
        return this.blockCommentEndDelimiter;
    }

    /**
     * @see SqlConfig#errorMode()
     */
    ErrorMode getErrorMode() {
        return this.errorMode;
    }

    /**
     * Provide a String representation of the merged SQL script configuration.
     */
    @Override
    public String toString() {
        return new ToStringCreator(this)
                .append("dataSource", this.dataSource)
                .append("transactionManager", this.transactionManager)
                .append("transactionMode", this.transactionMode)
                .append("encoding", this.encoding)
                .append("separator", this.separator)
                .append("commentPrefix", this.commentPrefix)
                .append("blockCommentStartDelimiter", this.blockCommentStartDelimiter)
                .append("blockCommentEndDelimiter", this.blockCommentEndDelimiter)
                .append("errorMode", this.errorMode)
                .toString();
    }

}
